1) The document summarizes work completed on deformable registration techniques and quality assurance (QA) processes during a work term. 2) For deformable registration, a phantom study was conducted to evaluate an open source registration algorithm, with results showing good agreement between reference and deformed contours. 3) For QA, a software called QATrack+ was developed to streamline daily, weekly, and monthly machine QA, storing results in a centralized database for easy review and trending of data. Future work is outlined to automate processes and improve customization and review of QA data.

1. Work Term #1
Summary of objectives and completed work
Matthew Strugari
May 2, 2014

2. Outline
• Background
• Workflow
• Calculations
• Results
• Future Work
Prostate
Deformable
Registration
• Background
• QATrack+
• Results
• Future Work
Quality
Assurance

3. Deformable Registration
Research Project #1

4. Deformable Registration
 A method of mapping two or more imaging data sets
Endo-rectal coil Endo-rectal coil
Prostate Prostate
Bladder

5. Deformable Registration
• Development and validation of an open
source deformable registration technique for
efficient integration of MR imaging into
radiation treatment planning
Synopsis
• To develop a phantom based method to
evaluate the efficacy of an established
deformable image registration technique
Goal

6. CIRS Multi-Modality Imaging Phantom
Fixed Image Moving Image
Water BagsWater Bags
Prostate
Endo-
Rectal
Coil
Urethra
Axial Slice

7. CIRS Multi-Modality Imaging Phantom
Fixed Image Moving Image
Prostate
Urethra
Endo-Rectal
Coil
Seminal
Vesicles
Seminal
Vesicles
Endo-Rectal
Coil
Fiducial
Marker
Prostate
Urethra
Fiducial
Marker
Sagittal Slice

8. General Workflow
• Contours are created using Aria Eclipse
treatment planning system
• Deformable registration technique is applied
using the 3D Slicer open source software
• Measurements and calculations are
performed directly within 3D Slicer

9. Contours - Prostate
Fixed Image Moving Image
“Eclipse”. Varian Medical Systems. 2014. 1 May 2014. <http://www.varian.com/us/oncology/radiation_oncology/eclipse/>.
Axial Slice

10. Import
Crop
Registration
Deform
Contours
Calculations
3D Slicer Workflow

11. 3D Slicer Workflow
Full Image
Cropped Image

12. B-Spline Deformable Registration
Process

13. 1. Defining Control Points
STANESCU, Teodor et al. Investigation of a 3D system distortion correction method for MR images. Journal of Applied Clinical Medical Physics, [S.l.], v. 11, n. 1, jan. 2010.
ISSN 15269914. Available at: <http://www.jacmp.org/index.php/jacmp/article/view/2961/1799>. Date accessed: 01 May. 2014. doi:10.1120/jacmp.v11i1.2961.

14. 2. Computing the B-Spline Functions
Spline
Basis Spline
•“Quadratic Spline”. Wikipedia. 29 Jan 2011. 1 May 2014. <http://en.wikipedia.org/wiki/File:Quadratic_spline_six_segments.svg>.
•Sharp, Gregory. “Cubic B-Splines”. Deformable Image Registration Using B-Splines. 10 Feb 2011. 1 May 2014.
<http://chapter.aapm.org/NE/DOCUMENTS/Presentations/2011Winter/sharp-neaapm-2011-02-10.pdf>.

15. 3. Computing the Deformation Field
vx(u)=∑iPiBi(u)
Sharp, Gregory. “Cubic B-Splines”. Deformable Image Registration Using B-Splines. 10 Feb 2011. 1 May 2014.
<http://chapter.aapm.org/NE/DOCUMENTS/Presentations/2011Winter/sharp-neaapm-2011-02-10.pdf>.

16. 4. Evaluating the Cost Function
Inflated vs. Deflated

17. 5. Optimization: Gradient Descent
vx(u)=∑iPiBi(u)
Gradient Descent Results

18. Algorithm Summary
Control
Point
Coefficients
B-Spline
Functions
Deformation
Vector Field
Cost
Function
Gradient
Descent
Control
Points
Deformed
Images

19. Results: Deformation Vector Field

20. Results: Deformation Vector Field

21. Results: Deformed Image
Fixed Image Deformed Image
Axial Slice

22. Results: Contour Deformation
Fixed Prostate
Deformed Prostate
Fixed Urethra Fixed Seminal Vesicle
Deformed Urethra Deformed Seminal Vesicle

23. Calculations: Dice Similarity Coefficient
Urethra Seminal Vesicles
Prostate

24. Calculations: Hausdorff Distance Metric
Axial Slice Sagittal Slice
“Hausdorff Distance Sample”. Wikipedia. 6 May 2008. 1 May 2014. <http://en.wikipedia.org/wiki/File:Hausdorff_distance_sample.svg>.

25. Calculation Results
Organ
Dice
Similarity
Coefficient
Hausdorff
Distance
(mm)
Reference
Volume
(cc)
Deformed
Volume
(cc)
Prostate 0.9733±0.0003 3.56±0.01 50.61 53.26±0.03
Urethra 0.917±0.001 2.40±0.10 3.265 3.529±0.009
Seminal
Vesicle
0.843±0.008 3.30±0.2 2.87 2.22±0.04

26. Conclusion
 It is possible to develop a phantom based method to
evaluate the efficacy of an established deformable
image registration technique
 The results for the main anatomical regions were
satisfactory

27. Conclusion
 This method can be applied to a number of different
modalities such as CT, CBCT, MR, and PET
 Deformable registration is useful for adaptive
radiotherapy to account for anatomical changes
throughout a patient’s treatment

28. Future Work
 Automating the process using Plastimatch
 Applying this process to in vivo data sets
 Finite element analysis for prostate deformation
using Elmer FEA

29. Quality Assurance (QA)

30. QA: Outlined by CPQR
Functionality Reproducibility Accuracy
“Emergency Stop”. Dreamstime. 2014. 1 May 2014. < http://www.dreamstime.com/photos-images/security-emergency-help-point.html>.
“The Life Cycle of a Website”. Standing Dog. 12 Mar 2013. 1 May 2014. < http://www.standingdog.com/blog/the-life-cycle-of-a-website/>.
“Accuracy and Precision”. Math is Fun. 2013. 1 May 2014. < http://www.mathsisfun.com/accuracy-precision.html>.

31. Machine QA
Daily
Weekly
Monthly
Annually
Radiation
Safety
Mechanical
Imaging
Dosimetry

32. Machine QA
CatPhan
“CatPhan©504 Manual”. The Phantom Laboratory. 2013. 1 May 2014. <http://www.phantomlab.com/library/pdf/catphan504manual.pdf>.
“Profiler 2”. Sun Nuclear Corporation. 2013. 1 May 2014. <http://www.sunnuclear.com/medPhys/machineqa/profiler2/profiler2.asp>.
“ArcCHECK”. Sun Nuclear Coroporation. 2013. 1 May 2014. <http://www.sunnuclear.com/medPhys/patientqa/arccheck/arccheck.asp>.

33. Current Condition of QA
 Argus implemented in SCC

34. QATrack+

35. QATrack+

36. QATrack+ Features

37. QATrack+ Features
Trendline
Reference Value Tolerance Level
Action Level
•Oasis Daily QA, 6 MV 10x10 output

38. QATrack+ Features
•Oasis Daily QA: 6 MV, 10 MV, and 15 MV 10x10 output
6 MV
15 MV
10 MV

39. Results
 Two complete months of daily QA data for all
machines
 QA data and results are kept in one location for daily,
weekly, and monthly QA

40. Results: Oasis
6 MV Daily6 MV Monthly
10 MV Daily
10 MV Monthly
15 MV Daily
15 MV Monthly

41. Conclusion
 QATrack+ saves time, effort, and money
 QATrack+ meets the CNSC standards and legal
requirements
 Records are stored to a database and are readily
available
 QATrack+ is fully customizable
 Unpredictable run times due to the use of QATrack+
software on a desktop computer

42. Future Work
 Modifications/elimination of weekly QA
 Implementation of monthly and annual QA
 Transfer QATrack+ to a server
 Regular review QA data
 E-mail notifications
 Setup of unique user groups and user accounts

43. Special Thanks
Saskatchewan Cancer Agency
Medical Physics: Deluan Tu; Niranjan Venugopal; Andrew
Alexander
External: Gregory Sharp, Medical Physicist (Massachusetts General Hospital);
Randle Taylor, Medical Physicist (Ottawa Hospital Cancer Centre)